Surface working mechanical tool for metal, stone and the like



Och 1967 TosHlo MIKIYA ET AL 3,344,868

SURFACE WORKING MECHANICAL TOOL FOR METAL, STONE AND THE LIKE 2Sheets-Sheet 1 Filed June 15, 1965 m m Ill/ll Oct. 3, 1967 TOSHIO MIKIYAET AL 4 SURFACE WORKING MECHANICAL TOOL FOR METAL, STONE AND THE LIKE 2Sheets-Sheet 2 Filed June 15, 1965 United States Patent 3,344,868SURFACE WORIGNG MECHANICAL TOOL FOR METAL, STONE AND THE LIKE ToshioMikiya and Yukio Aoki, Ota-ku, Tokyo, Japan, assignors to Nitto KohkiCompany Ltd., Ota-ku, Tokyo, Japan, a Japanese corporation Filed June15, 1965, Ser. No. 464,054 Claims priority, application Japan, June 17,1964, 39/34,418 3 Claims. (Cl. 173-114) This invention relates to asurface working mechanical tool for metal, stone and the like.

It has been well known that, in a surface working mechanical tool formetal, stone and the like, a pin cluster holder in which a plurality ofpins are mounted is pneumatically operated so as to retire towards apiston, and the pins are projected by a dashing power of the pistonintermediate a throttle anvil so that the tips of the pins act on asurface to be worked. In accordance with such prior arts, the compressedair which operates the pin cluster holder is admitted into a cylinderregardless of the operation of the piston. It is difiicult therefore tooperate the pin cluster holder in such a manner that the same carryingthe pins is advantageously in a retired position when the piston is atthe highest speed. 7

The principal object of this invention is to provide a surface workingmechanical tool in which a pin cluster holder is advantageously in aretired position when a piston is at the highest speed.

Another object of this invention is to provide a surface workingmechanical tool of the character referred to that will be of simplestructure and not likely to get out of order.

Still another object of this invention is to provide a surface workingmechanical tool of the class described which also blows away chipsautomatically.

Briefly stated in accordance with one aspect of this invention, there isprovided a surface working mechanical tool for metal, stone and thelike, comprising a piston adapted to reciprocate in a cylindrical memberby the action of compressed air admitted into an inside cavity formed inthe piston, a pin cluster holder adapted to reciprocate in an extendedcylindrical member, and a throttle anvil interposed between said pistonand said pin cluster holder in said extended cylindrical member. Thecompressed air is supplied through a main air port provided in thepiston. The pin cluster holder carries a plurality of pins having headsin such a manner that the pins are axially-slidably countersunk into thepin cluster holder on the rear surface thereof, respectively. The pinsare projected forwards by a dashing power of the piston intermediate thethrottle anvil so that the tips of the pins impulsively act on a surfaceof work, respectively. The surface working mechanical toolfurthercomprises a small air port provided in the piston in front of the mainair port and adapted to pass air from the inside cavity to an airoutlet, a frontward step provided around the pin cluster holder, and anumber of flutes and second air inlets adapted to communicate the airoutlet with a space in front of the step. The air outlet is adapted tobe communicated with the main air port through the inside cavity and thesmall air port so as to admit the compressed air into the space andsubsequently with the inside cavity through the main air port so as toexhaust air held inside the piston to the same space whereby the pincluster holder carrying the pins is made to retire towards the throttleanvil.

The invention will be better understood and other objects and additionaladvantages of the invention will become apparent upon perusal of thefollowing description taken in connection with the drawings, in which:

1 FIG. lis an axial sectional view of a surface working 3,344,868Patented Oct. 3, 1967 mechanical tool embodying this invention and showsa position where the pin cluster holder is retiring while the piston isjust started forwards;

FIG. 2 is a cross sectional view on line IIII of FIG. 1;

FIG. 3 is a view similar to FIG. 1, but showing an instance where thepiston strikes the throttle anvil and the pin cluster holder has beenretired ultimately; and

FIG. 4 is another view similar to FIG. 1, but showing a position wherethe pin cluster holder and pins are projected forwards so as to work bythe tips of the pins while the throttle anvil has been almost stayed andthe piston is being retired.

Referring more particularly to the drawings, the preferred embodiment ofthis invention will now be descirbed; however, this description will beunderstood to be illustrative of the invention and not as limiting it tothe particular constructon shown and described. A cylindrical member 3is provided inside a body 1 secured thereto. The rear end of thecylindrical member 3 is sealed by a threaded rear stopper 4 screwedtherein. The front end of the cylindrical member 3 is radially expandedand axially extended into an extended cylindrical member 2 intermediatea flange 2a. The front end of the extended cylindrical member 2 issealed by a threaded front stopper 5 having a central opening. A piston6 is provided in the cylindrical member 3 so as to be slidable axiallyin the latter. The hind part of the piston 6 is somewhat expandedradially so that the peripheral surface of the hind part of the piston 6is adapted to be slidable axially on the hind part of the inside wall ofthe cylindrical member 3, while the fore part of the cylindrical member3 is somewhat narrowed radially so that the peripheral surface of thefore part of the piston 6 is adapted to be slidable axially on the forepart of the narrowed inside periphery of the cylindrical member 3. Thereis provided a shoulder 6a intermediate the fore part and the hind partof the piston 6. A corresponding shoulder is formed between the forepart and the hind part of the inside wall of the cylindrical member 3.

A number of air inlets 10. are provided through the hind part of thewall of the cylindrical member 3, which is communicated with an air pipe1a provided through the body 1 so as to supply com-pressed air from asource .(not shown) to the air inlets 10. The piston 6 has a rearopenaxial cavity 11a, the interior space of which is adapted to becommunicated with the air inlets 10 through the annular space betweenthe two shoulders and a number of main air ports 11 provided radiallythrough the fore part of the piston 6. A small air port 12 is providedradially through the piston 6 so as to communicate the inside cavityspace 11a with a number of air outlets 13 provided radially through thefore part of the cylindrical member 3 when the piston 6 is rather in thehind position. However, when the piston 6 is in the fore position, theair outlets 13 is communicated with the inside cavity 1111 through themain air ports 11, while the air inlet 10 is closed.

There is a throttle anvil 7 inside the extended cylindrical member 2,being adapted to be slidable axially on the inside periphery of theextended cylindrical member 2. However, it is not necessary to slide thethrottle anvil 7 so far from the flange 2a. There is a pin clusterholder 9 having a radially expanded rear part and a rather narrowed forepart. The radially expanded rear part is adapted to be slidable axiallyon the inside periphery of the extended cylindrical member 2. The forepart of the pin cluster holder 9 is adapted to be slidable axially onthe inside periphery of the central opening of the threaded f-rontstopper 5. Thus a frontward step 15 is formed between the peripheries ofthe radially expanded rear part and the fore part of the pin clusterholder 9. An annular space is formed between the frontward step J andthe rear end of the threaded front stopper 5. A number of flutes 14 areprovided in the inside wall of the body 1 in such a manner that the rearends of the flutes 14 are communicated with the air outlets 13 and thefront ends thereof are communicated with a number of second air inlets16 provided radially through the fore part of the extended cylindricalmember 2 so as to communicate the air outlets 13 with the space in frontof the step 15. There are provided a number of radial sec ond airoutlets 17 for exhausting air in the space in front of the step 15 whenthe pin cluster holder 9 has been retired. It is a well known structurethat the air pipe 1a is communicated with the main air ports 11, while,in accordance with this invention, there is provided an annular groovein the inside Wall of the body 1. The annular groove is air-tightlyshielded from the air pipe 1a by a bulkhead 1b and leads to the flutes14. The

radially expanded rear part of the pin cluster holder 9 is provided witha number of axial holes. Pins 8 are countersunk at their rear expandedends in the rear ends of the axialholes and adapted to be slidableaxially in the axial holes, respectively. The front ends or tips of thepins 8 are extended through and projected beyond the central opening ofthe threaded front stopper 5,'respectively.

In operation, the piston 6 starts its forward motion by the action ofcompressed air admitted from the air pipe 1a into the axial cavity 11athrough the air inlets 10, the clearance between the inside periphery ofthe cylindrical member 3 and the outside periphery of the piston 6, andthe main air ports 11, as shown in FIG. 1. At the same time, thecompressed air admitted into the axial cavity 11a is further'led to' theflutes 14 through the small air port 12 and the air outlets 13 whencethe air is passed through the second air inlets 16 to the annular spacein front of the frontward step 15 so as to slide the pin cluster holder9 rearwards. It is the position that FIG. 3 shows, Where the piston 6 ismost accelerated. At that time, the throttle anvil 7 and the pin clusterholder 9 are in'the rearmost position thereof and the throttle anvil 7is in contact with the pin cluster holder 9 and the expanded heads ofthe pins 8. By virtue of the structure in accordance with thisinvention, it is possible to cooperate the operation of the piston 6with the retiring motion of the pin cluster holder 9 so that the piston6 strikes the throttle anvil 7 when the former is at the highest speedand at the same time when the pin cluster holder 9 has just comein'contact withthe throttle anvil'7. By virtue of the provision of theflange 2a between the cylindrical member 3 and the expanded cylindricalmember 2, the rearward motion of the throttle anvil 7 is restricted bythe flange 2a so that the throttle anvil 7 is prevented from 'anexcessive retirement whereby it is possible to strike'it by the piston 6at the highest speed thereof simultaneously with the contact of thethrottle anvil 7 with the pin cluster holder 9. Thus the kinetic energyof the piston 6 is transmitted most effectively to the pin clusterholder 9 and the pins 8 intermediate the throttle anvil 7 without anymis-hit. The transmission of energy is rendered inthe accuratelyrequired position. When the pin cluster holder 9 has been energized asabove, thethrottle anvil 7 itself is deenergized so that it does notmove forwards appreciably. However, when the tool is positioned frontside down, it is probable that the throttle anvil 7 slides forwards bygravity; As it'is neces- 'sary to retire the throttle anvil 7 to itsrearmost position for the next cycle, it is preferred to provide asuitable means (not shown) for anchoring the throttle anvil 7 to therear position. Mean-time, the piston 6 is retired by the reaction asshown in FIG. 4.

The pin cluster ho-lder 9 is made to retire to the rear position asexplained hereinbefore. However, the action of the compressed airadmitted into the second air inlets 16 through the small air port 12only during the latter is communicated with the air outlets 1-3is notsuflicien-t for retiring the pin cluster holder 9 so far as the positionof in contact with the throttle anvil 7, because of the fact that thecross sectional area of the small air port 12 is far smaller than thatof the main air ports 11. Under these circumstances, when the piston 6has been advanced so as to disengage the small air port 12 from the airoutlets 16, the main air ports 11 are positioned in communication withthe air outlets 13 so as to exhaust air from the inside axial cavity 11ato the second air inlets 16 through the same passage as above. Even theair has been expanded within the inside axial cavity 1 11:, it has stillsubstantial pressure and is voluminous so that the pin cluster holder 9which has been retired substantially is further retired so far as theposition of in contact with the throttle anvil 7 by the action of theexhausted air acting on the frontward step 15. When the pin clusterholder 9 has been retired to the rearmost position, the second airoutlets 17 is communicated with the space in front of the fro-ntwardstep 15 so as to exhaust air from the tool. In accordance with the priorart, a passage of exhausting air which has driven the piston is providedapart from a passage for leading air for driving the pin cluster holder.By virtue .of this invention, such a structure is simplified so as to beeasily designed. In addition, all volume of the exhausted air isdirected to the tips of pins so that the chips are blown away from thesurface to be worked.

While a particular embodiment of this invention has been illustrated anddescribed, modifications thereof will readily occur to those skilled inthe art. It should be understood therefore that the invention is notlimited to the particular arrangement disclosed but the appended claimsare intended to cover all modifications which do not depart from thetrue spirit and scope ofthe invention.

What isclaimed as new and desired to be secured by Letters Patent of theUnited States is:

1. A surface working mechanical tool for metal, stone and the like,comprising a piston having an inside cavity and adapted to reciprocatein a cylindrical member by the action of compressed air admitted intosaid cavity through at least a main air port provided in said piston, apin cluster holder adapted to reciprocate in an extended cylindricalmember, said pin cluster holder carrying a plurality of pins havingexpanded heads in such a manner that the pins are axially slidablycountersunk into said pin cluster holder on the rear surface thereof,respectively, a throttle anvil interposed between said piston and saidpin cluster holder in said extended cylindrical member, said pins beingprojected forwards by a dashing power of said piston intermediate saidthrottle'anvil so that the tips of said pins impulsively act on asurface of work, respectively, a small air port provided in said pistonin front of said main air port and adapted to pass air from said insidecavity to at least an air outlet,- a frontward step provided around saidpin cluster holder, and a number of flutes and second 'air inletsadapted to communicate said air outlet with a space in front of saidstep, said air outlet being adapted to be communicated with said mainair port through said inside cavity and said small air port so as toadmit said compressed air into said space and subsequently with saidinside cavity through said main air port so as to exhaustair held insidesaid piston to the same space whereby said pin cluster holder carryingsaid pins is made to retire towards said throttle anvil. Y

2. A surface working mechanical tool for metal, stone and the likecomprising a body having a cylindrical memher and an extendedcylindrical member, a piston having an inside cavity and adapted toreciprocate in said'cylindrical member by the action of compressed airadmitted into said' inside cavity through at least a'main air portprovided in said piston, a pin cluster holder adapted to reciprocate insaid extended cylindrical member, said pin cluster holder carrying aplurality of pins having expanded heads in such a mannerthat the pinsare axially slidably countersunk into said pin cluster holder on therear surface thereof, respectively, a throttle anvil interposed betweensaid piston and said pin cluster holder in said extended cylindricalmember, said pins being projected forwards by a dashing power of saidpiston intermediate said throttle anvil so that the tips of said pinsimpulsively act on a surface of work, respectively, and an air supplyingsystem for driving said pin cluster holder, comprising a small air portprovided in said piston in front of said main air port, at least an airoutlet provided through said cylindrical member, an annular grooveprovided in the inside wall of said body, a number of axial flutesprovided between said body and said extended cylindrical member, and anumber of second air inlets provided through said extended cylindricalmember, said air outlet being adapted to be communicated commonly butalternately with said main air port so as to admit said compressed airinto said air outlet through said main air port, said inside cavity, andsaid small air port and subsequently admit exhausted air from saidinside cavity into said air outlet through said main air port, and saidcompressed air and said exhausted air being directed from said airoutlet to a frontward step provided around said pin cluster holderthrough said annular groove, said flutes, and said second air inlets soas to retire said pin cluster holder towards said throttle anvil.

3. In a surface Working mechanical tool comprising a casing havingrespective front, intermediate and rear connecting bores having a commonlongitudinal axis, said front bore extending to the front of saidcasing, said intermediate bore of greater diameter than the other boresto define respective front and rear stop shoulders at the respectivejunctions of said intermediate bore with said front and rear bores, apiston having a hollow piston bore frictionally slidably received withinsaid rear bore and adapted to protrude into said intermediate bore, ananvil frictionally slidably received within said intermediate bore andadapted to seat against said rear shoulder, a pin cluster holder havinga hollow shank frictionally slidably received within said front bore anda head of increased diameter frictionally slidably received within saidintermediate bore, said head having through longitudinal head borescommunicating with the hollow shank space, and pins slidably receivedwithin said head bores and protruding forwardly of said casing; theimprovement wherein said casing has a compressed air inlet communicatingwith said rear bore, said piston having a main radial port extending toits bore and communicating with said casing inlet except in the forwardposition of said piston, said piston having an auxiliary air portextending to its bore and located forwardly of and of smaller diameterthan said main air port, said casing having air passage meanscommunicating between said rear bore intermediate said air inlet and thefront of said rear bore and said intermediate bore forwardly of saidhead, said main port communicating with said air passage means and saidauxiliary port out of communication therewith in forward piston positionand vice versa in rearward piston position, said ports positioned anddimensioned relative to said casing inlet and said air passage meanswhereby compressed air entering said piston bore from said casing inletthrough said main port forces said piston to its forward position and atthe same time passes through said auxiliary port and said air passagemeans to drive said holder head rearwardly, said holder head therebyabutting said anvil and said piston striking said anvil, said pins beingthereby driven forwardly, said piston being then adapted to exhaust airthrough said main port and said air passage means whereby to raise saidholder head again.

References Cited UNITED STATES PATENTS 842,655 1/1907 Hardsoeg 1731141,076,246 10/1913 Smith 173-64 1,583,288 5/1926 Gilman 173--1051,747,164 2/1930 Ditson et al. 173114 X 2,356,314 8/1944 Gray et al.2981 2,613,647 10/1952 Curtis 17363 2,672,129 3/1954 Fischer 173-682,672,677 3/1954 Von Arx 2981 FOREIGN PATENTS 1,348,165 11/1963 France.

HAROLD D. WHITEHEAD, Primary Examiner.

1. A SURFACE WORKING MECHANICAL TOOL FOR METAL, STONE AND THE LIKE,COMPRISING A PISTON HAVING AN INSIDE CAVITY AND ADAPTED TO RECIPROCATEIN A CYLINDRICAL MEMBER BY THE ACTION OF COMPRESSED AIR ADMITTED INTOSAID CAVITY THROUGH AT LEAST A MAIN AIR PORT PROVIDED IN SAID PISTON, APIN CLUSTER HOLDER ADAPTED TO RECIPROCATE IN AN EXTENDED CYLINDRICALMEMBER, SAID PIN CLUSTER HOLDER CARRYING A PLURALITY OF PINS HAVINGEXPANDED HEADS IN SUCH A MANNER THAT THE PINS ARE AXIALLY SLIDABLYCOUNTERSUNK INTO SAID PIN CLUSTER HOLDER ON THE REAR SURFACE THEREOF,RESPECTIVELY, A THROTTLE ANVIL INTERPOSED BETWEEN SAID PISTON AND SAIDPIN CLUSTER HOLDER IN SAID EXTENDED CYLINDRICAL MEMBER, SAID PINS BEINGPROJECTED FORWARDS BY A DASHING POWER OF SAID PISTON INTERMEDIATE SAIDTHROTTLE ANVIL SO THAT THE TIPS OF SAID PINS IMPULSIVELY ACT ON ASURFACE OF WORK, RESPECTIVELY, A SMALL AIR PORT PROVIDED IN SAID PISTONIN FRONT OF SAID MAIN AIR PORT AND ADAPTED TO PASS AIR FROM SAID INSIDECAVITY TO AT LEAST AN AIR OUTLET, A FRONTWARD STEP PROVIDED AROUND SAIDPIN CLUSTER HOLDER, AND A NUMBER OF FLUTES AND SECOND AIR INLETS ADAPTEDTO COMMUNICATE SAID AIR OUTLET WITH A SPACE IN FRONT OF SAID STEP, SAIDAIR OUTLET BEING ADAPTED TO BE COMMUNICATED WITH SAID MAIN AIR PORTTHROUGH SAID INSIDE CAVITY AND SAID SMALL AIR PORT SO AS TO ADMIT SAIDCOMPRESSED AIR INTO SAID SPACE AND SUBSEQUENTLY WITH SAID INSIDE CAVITYTHROUGH SAID MAIM AIR PORT SO AS TO EXHAUST AIR HELD INSIDE SAID PISTONTO THE SAME SPACE WHEREBY SAID PIN CLUSTER HOLDER CARRYING SAID PINS ISMADE TO RETIRE TOWARDS SAID THROTTLE ANVIL.